Design/Shape: The design of you robot is one of the most important parts, some take it further then others. We never had any proper drawings or designs, just the odd skecths, we built the robot around everything. Some people design the whole robot on a CAD system then have it made, its then just a case of bolting it together, some robots have done this successfully, like Big Nipper. But one mistake in the design can be very costly.

Merlin has good and bad design features, as do most. Normally robots are designed around the weapon.

Another thing is to decided if you are going to build and chassis based robot or a monocoque (don’t know how you spell it!). Chassis based robots are like Merlin, Bigger Brother and M2, it means you build a chassis, everything is mounted then to it. The armour is then added and made removable. Monocoques, are robots such as S3 and Plunderbird. This means you armour and chassis are one piece. This can save weight but normally makes it harder to work on. There are also robots that are cross between both, such as Dantomkia and Stinger. This gives you the best of both worlds, but again can have set backs.

Armour: This is another important factor, as this will take the brunt of most attacks. There are a few main options;

Polycarbonate (Lexan/Macrolon): This gives good strength against most attacks, and is very light, but can be expensive.

Steel: One of the most popular, its strong against most attacks. Its very cheap and easy to work with, but it is very heavy.

Aluminium: This is light, cheap and easily available. But needs to be thick to withstand disc attacks.

Titanium: Very strong and light, but very expensive! Well worth the investment.

Others: There are other options such as fibreglass, nylon and wood.

Transmission: There are two main options when coming to transmission, the first being gears and the other being roller chain. Each have their advantages and dis-advantages.

Chain: This is probably the most common, it is cheap and easy to build into a robot. In a heavyweight you want about 3/8 pitch. The best thing about them is they are very forgiving so they allow for errors! Their main problem is them slipping and jumping off, but it the chain is the correct tension, it should be no problem.

Gears: These are probably more efficient and reliable. But they need to be set up correctly, and have solid support. If not they can strip and jump.

Other options include belts, these rarely used in heavyweights due to the power needing to be transmitted. Some feathers have ran successfully with belts.

Locomotion/Gear reduction: Choosing a reduction can be as important as the weapon, if the reduction isn’t correct then your not a lot of good. The unwritten rule is; The diameter of the wheel (in inches) is the reduction needed. This assuming a Bosch 750 is used. We have 10” wheels, but we run an 8:1 reduction to give us abit more speed (top speed of 15mph). Some gear higher then this, M2, Dantomkia and Mute all use about 6.5:1, this gives them a top speed of about 20mph, but not much pushing power. I suggest using John Ried’s Drive train Calculator to help when deciding.

Locomotion is another factor, if using tracks then you want abit more torque. Tracks can be fun and look good, but can be unreliable and a pain to fix. Wheels are nice and simple, and work well. The most common wheels are Go-Kart wheels.

Power: The two options are Petrol and electric. Petrol gives good power to weight ratio, but can be unreliable. Electric is the most common, it is; clean, easy to work with. The two main options with electric is SLA (sealed lead acid) and NiCad.

SLAs: These can be cheap and readily available. Some makes are better then others but it depends on the money available. Hawkers are the best type for robots, they are efficient and can supply high currents. They also can be charged quickly. Some types although good, cant supply the currents demanded.

NiCads: These are becoming more popular. They are more efficient then SLAs and are lighter. They can be charged quickly and can supply high currents. They also have the benefit of being able to be customised to the size needed. The most common type is the Sanyo 3Ah cells. We use these on our feathers. Many Heavyweights are now using them. Storm 2 has had great results from them. Many are now switching to them, such as Mute, M2 and Can Opener. Once our SLAs become warn, we may switch to them. Although expensive, you can get away with having just one set as they can be charged in less then an hour.

Speed controllers: Assuming you are using Bosch 750s, then there are a lot of options now available. Before there just to be 4qd and Vantec. There are now about 5 main types. It all depends on the money available and the features you require.

4QD : Nice and cheap, although the NCC and PRO series still use relay changeover they have performed well. A range of interfaces are now available.

Vantec: Good quality, high response and tough as hell, but expensive. They also are made in the USA therefore they need to be shipped over for repair.

AX2550 A new controller form the USA, very high spec, with everything you need. They have the bonus of Technobots being the UK supplier, so service isn’t a problem.